/*
 * Copyright (c) 2012, marco.tamburelli@gmail.com
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * The views and conclusions contained in the software and documentation are those
 * of the authors and should not be interpreted as representing official policies, 
 * either expressed or implied, of the CometMI Project.
 */
package org.cometmi.gwt.server;

import java.io.IOException;
import java.util.List;

import org.apache.log4j.Logger;
import org.cometmi.gwt.server.MiBox.DeferredPoller;
import org.cometmi.gwt.server.MiBox.LogicalQueue;
import org.cometmi.gwt.shared.MiManager;
import org.cometmi.gwt.shared.MiProxyManager;
import org.cometmi.gwt.shared.MiQueue;
import org.cometmi.gwt.shared.MiTransaction;
import org.cometmi.gwt.shared.MiTransactionManager;
import org.cometmi.gwt.shared.events.AttributesCallback;
import org.cometmi.gwt.shared.events.BindCallback;
import org.cometmi.gwt.shared.exceptions.NameParseException;
import org.cometmi.gwt.shared.exceptions.NotAllowedQueueException;
import org.cometmi.gwt.shared.request.Call;

import com.google.gwt.user.client.rpc.SerializationException;

public class MiQueueServer extends MiQueue
{
	static protected Logger logger = Logger.getLogger(MiQueueServer.class);

	private MiBox miBox;
	private LogicalQueue q;

	private boolean bindAllowed;

	/**
	 * Creates an object referencing a queue. The created object is a
	 * {@link MiQueue} referencing a {@link LogicalQueue} element which:
	 * 
	 * 
	 * 1. The queue has not yet defined credentials, in such case are
	 * credentials are provided and access right are warranted.
	 * 
	 * 2. Creadentials are defined, in such case the access right is warranteed
	 * only in case defined credentials match provided ones.
	 * 
	 * Warning: The provided logical queue q, should be not null.
	 * 
	 * @param q The {@link LogicalQueue} to which this object points.
	 * @param miBox {@link MiBox} instance.
	 * @param credentials Credentials certificate of the current user.
	 */
	protected MiQueueServer(LogicalQueue q, MiBox miBox, String credentials)
	{
		super();

		if (q.descriptor.ownerCredentials == null)
		{
			q.descriptor.ownerCredentials = credentials;
			this.bindAllowed = true;
		}
		else
			this.bindAllowed = q.descriptor.ownerCredentials.equals(credentials);

		super.queueExpression = q.queueName;
		super.proxyFactory = miBox.proxyFactory;
		super.wrapperFactory = miBox.wrapperFactory;

		this.miBox = miBox;
		this.q = q;
	}

	@Override
	public void bind(BindCallback callback)
	{
		if (callback == null) callback = new BindCallback()
		{
			@Override
			public void onSuccess()
			{}

			@Override
			public void onError(Throwable t)
			{}
		};

		if (!this.bindAllowed)
		{
			callback.onError(new NotAllowedQueueException("Queue " + super.queueExpression + " is already bound"));
			return;
		}

		if (super.connected) return;

		final BindCallback callback_ = callback;

		try
		{
			super.connected = true;

			this.miBox.poll(super.queueExpression, new DeferredPoller()
			{
				@Override
				public void onPoll(List<Call> elems) throws SerializationException, IOException
				{
					try
					{
						MiQueueServer.this.manageResponse(elems);

						if (isDisconnecting())
							forceDisconnect();
						else
							MiQueueServer.this.miBox.poll(MiQueueServer.this.queueExpression, this);
					}
					catch (Throwable e)
					{
						callback_.onError(e);
						forceDisconnect();
					}
				}

				@Override
				public boolean isActive()
				{
					return isConnected();
				}
			});
		}
		catch (Throwable e)
		{
			callback.onError(e);
			forceDisconnect();
		}
	}

	@Override
	public void unbind(BindCallback callback, boolean discard)
	{
		if (callback == null) callback = new BindCallback()
		{
			@Override
			public void onSuccess()
			{}

			@Override
			public void onError(Throwable t)
			{}
		};

		requestDisconnect();

		try
		{
			this.miBox.freeQueue(super.queueExpression, discard);
		}
		catch (Throwable e)
		{
			callback.onError(e);
		}
	}

	@Override
	protected void onResponse(List<Call> calls) throws Exception
	{
		manageResponse(calls);
	}

	@Override
	protected MiManager provideMiManager(boolean transactional)
	{
		if (transactional)
			return new MiTransactionManager();
		else
			return new MiProxyManager()
			{
				@Override
				protected void publish(List<Call> calls)
				{
					try
					{
						MiQueueServer.this.miBox.publish(super.queues.getExpression(), calls);
					}
					catch (Exception e)
					{
						logger.error("[MiQueueServer] an error occurred while publishing: ", e);
					}
					catch (NameParseException e)
					{
						/* This exception shouldn't be never raised */
						logger.error("Strange exception", e);
					}
				}
			};
	}

	@Override
	public MiTransaction createTransaction()
	{
		return new MiTransaction(this)
		{
			@Override
			protected void publish(List<Call> calls)
			{
				try
				{
					MiQueueServer.this.miBox.publish(super.queues.getExpression(), calls);
				}
				catch (Exception e)
				{
					logger.error("[MiQueueServer] an error occurred while publishing: ", e);
				}
				catch (NameParseException e)
				{
					/* This exception shouldn't be never raised */
					logger.error("Strange exception", e);
				}
			}
		};
	}

	@Override
	public void setAttribute(String key, String value, AttributesCallback callback)
	{
		if (this.bindAllowed)
			this.q.descriptor.attributes.put(key, value);
		else
		{
			if (callback == null) callback = new AttributesCallback()
			{
				@Override
				public void onError(Throwable t)
				{}

				@Override
				public void onSuccess(String value)
				{}
			};

			callback.onError(new NotAllowedQueueException("Queue " + this.queueExpression + " could be already bound"));
		}
	}

	@Override
	public String getAttribute(String key, AttributesCallback callback)
	{
		if (callback == null) callback = new AttributesCallback()
		{
			@Override
			public void onError(Throwable t)
			{}

			@Override
			public void onSuccess(String value)
			{}
		};

		String value = this.q.descriptor.attributes.get(key);
		callback.onSuccess(value);

		return value;
	}

	@Override
	public String removeAttribute(String key, AttributesCallback callback)
	{
		if (callback == null) callback = new AttributesCallback()
		{
			@Override
			public void onError(Throwable t)
			{}

			@Override
			public void onSuccess(String value)
			{}
		};

		if (this.bindAllowed)
		{
			String value = this.q.descriptor.attributes.remove(key);
			callback.onSuccess(value);

			return value;
		}
		else
		{
			callback.onError(new NotAllowedQueueException("Queue " + this.queueExpression + " could be already bound"));

			return null;
		}
	}
}
